Seagrass rehabilitation project

Seagrass meadows are an important habitat and food source for a range of marine species, including commercially important fishery stocks. These underwater meadows are also important for seabed stability, as their roots stabilise the sediments that they occur in. Over the last 60 years, seagrass has been declining across the Adelaide metropolitan coastline.

Natural Resources Adelaide and Mount Lofty Ranges (AMLR) supports South Australian Research and Development Institute and Flinders University to establish practical ways of restoring seagrass off our coast.

What is being done?

Trials have been undertaken to establish a material that can be placed on the sea floor to help young seagrass to grow.

After earlier work on different materials, the trials now focus on using hessian bags placed on the sea floor. These provide an anchor point for young seagrass to attach to amongst bare sand. Key challenges have been finding a bag material or coating that allows the seedlings to attach and grow through, and making the bag last until the plants are established. The bag fill is also important and can affect the growth of seedlings. Trials are also revealing useful information about seagrass life history.

Surveys to measure seagrass health in the region have also been developed. These surveys have been run offshore from the Bungala and Yankalilla estuaries on the Fleurieu Peninsula and at metropolitan sites of Largs Bay, Semaphore, Grange and Henley. The Fleurieu seagrass surveys establish a baseline to measure catchment water quality.

Seagrass meadows at Yankalilla Bay currently appear to be in good health.